[4] In 1882, Syed Mahmood received his first officiating appointment as a judge to the High Court of the North-Western Provinces in Allahabad, with active lobbying on his behalf by the Viceroy who had replaced Lytton, Lord Ripon.

[5] His contemporaries generally considered him to have an exceptional ability, assisted by a knowledge of the Arabic language that he had gained while studying in Cambridge and which was invaluable for assessing Muslim law.

Whitley Stokes, Law Member of the Viceroy's Legislative Council in India during the years 1877 to 1882, later praised Mahmood's judgments in his Anglo-Indian Codes.

[6] Likewise, in an obituary he wrote, Tej Bahadur Sapru, a younger contemporary of Mahmood's, commented that his long and detailed judgments were necessary because of the spate of new legislation being enacted that needed to be clarified in a court of law.

"[3] His prolixity and frequent dissenting opinions were a couple of the factors that led to conflicts with his fellow judges, and eventually to an early retirement in 1893.

[3] After his retirement from the judiciary, he returned to his legal practice as a barrister, working in Lucknow as well as serving on the North-Western Provinces and Oudh Legislative Council from 1896 to 1898.

[9] He then assisted his father, Sir Syed, in founding the Muhammadan Anglo-Oriental College at Aligarh, and continued to play a vital role in its administration even while working as a lawyer and judge in Allahabad.

In 1888, Syed Mahmood married Musharraf Jahan, the daughter of Nawab Khwajah Sharfuddin Ahmad, his father's maternal cousin.

Syed Mahmood's first contribution to the legal literature of British India was an Urdu translation of the 1872 Law of Evidence and subsequent amendments, published in 1876.

But his major written contribution consisted of the approximately 300 legal judgments recorded in the Indian Law Reports: Allahabad Series between the years 1882 and 1892, a considerable number of which were over twenty pages in length.